* U.S. stocks fell on Thursday as a stronger dollar weighed on oil and other commodity prices, sending energy and materials sectors lower, a day after Federal Reserve statements appeared to be more dovish than expected even as it opened the door for a Fed funds rate hike as soon as in June. * Greek Prime Minister Alexis Tsipras said during late-night crisis talks in Brussels that his leftist-led coalition would present a full set of economic reforms in order to unlock cash to stave off bankruptcy.